EARTH'S PROTECTIVE SHIELD. Earth is surrounded by invisible gases that form a thin protective blanket that we call the atmosphere. It contains the oxygen that we breath as well as other important gases such as nitrogen, carbon dioxide, water vapor, and ozone.
Answer:
The correct answer is d the positive feed back reduces change in the the system
Explanation:
In an biochemical reaction when the released product stimulate the release and activation of the same product and act together to exibit their biological function, then this type of regulation is called positive feedback.
The positive feed back mechanism leads to increased change in the system that"s why it is named so.
For example during blood clotting platelets molecules are released to form clots to stop bleeding. one activated platelet can stimulates the activity of other platelets which then join together to form a group for generating further blood clots.
A............................................
Chemotherapy is a term which we usually related to the treatment of cancer. In cancer the malignant cell keeps on dividing themselves and also infect the near by cell to enter into a phase of no restrictive division. In chemotherapy, a drug or medicine either individually or in combination with other medicines is either directly introduced in the blood or is injected only on the targeted cell. The chemotherapy interacts with the cell division process of the cell directly or indirectly. In the direct process the cell division process either mitosis or meiosis is impaired or the essential hormones or enzymes required for cell divisions are attacked through cytotoxic drug. It also inhibits cell division through apoptosis strategy where the cancerous cell starts dividing themselves. The chemotherapy process is to be done regularly over a certain period of time. Usually the treatment course occurs from a day to few weeks’ time. The dosage of chemical is given either orally or injected into the body fluid or either through intravenously.
Apart from benefits there can be several side effects of chemotherapy:
a) A patient may get pucky feelings and in some cases may have nausea or vomiting
b) There are also chances of hair loss.
c) It can also adversely affect the skin, as it may get dry or oversensitive.
d) The blood platelet count may decrease
e) There can be chances of hearing and vision impairment.
